INTRODUCTION::
We performed a pilot study examining the safety and tolerability of valacyclovir in veterans with herpes simplex virus type 2 and hepatitis C virus (HCV) coinfection.

METHODS::
We performed a randomized double-blind, placebo-controlled, crossover clinical trial in U.S. veterans with genotype 1 HCV/herpes simplex virus type 2 coinfection. Patients were randomized 1:1 in blocks of 10 to receive either 1 g twice-daily valacyclovir or matching placebo for 8 weeks followed by a 2-week washout phase with daily placebo. The alternate therapy (valacyclovir or placebo) was given for an additional 8-week period. Safety assessments were performed every 2 weeks. Changes in HCV RNA and alanine aminotransferase (ALT) were estimated using linear mixed models (SAS Proc Mixed).